Currently, assays are read by human eye or high cost imaging system and the reading of assays are determined by individual human judgment or expensive equipment. The purpose of reading these assays is to determine whether a test sample of biological or chemical material being assayed includes a particular analyte, or a derivative or constituent of the analyte. The particular analyte, which is the subject of the assay, is referred to as a test analyte. The test sample may include biological material such as urine, saliva, blood plasma, or the like. The test sample may include chemical material such as rainwater, sludge, or the like.
An assay is performed using a substrate having a sensitive region patterned on the surface of the substrate. Such substrates may include channels that wick the test sample up and over the sensitive regions patterned within the channels. In some case, the substrate is made of silicon or glass and has a smooth surface. If the substrate includes channels, the channels are etched in the substrate and the sensate region is patterned within the etched channels. In other cases, the substrate is made of paper. If the paper substrate includes channels, the channels are defined by the type and/or density of the paper or by thickness variations in the paper.
The sensitive region reacts to exposure of a test analyte. The sensitive region is indistinguishable from the substrate outside the sensitive region until the sensitive region is exposed to the test analyte. The reaction can be a bonding of the material in the sensitive region with the test analyte. The reaction is detected by an emission of light from the reacted region. In some cases, light is incident on the assay after exposure to a test sample. If a reaction has occurred, some of the incident light is reflected from the bonded material. For example, gold atoms are attached to the test analyte and incident light is reflected from the bound gold atoms. In other cases, if a reaction has occurred, the bonded material fluoresces upon exposure to the incident light.
A human observes the sensitive region to determine if there was a sufficient change in the appearance of the sensitive region relative to the rest of the substrate. When readings to determine an exposure of the sensitive region to of a test analyte are made by the human eye, the readings may not be consistent and may be prone to error. When assays are read by equipment, such as a charge-coupled device (CCD), the determination of an exposure of the sensitive region to of a test analyte may be consistent and relatively error free. However, the equipment typically must be high resolution to make the accurate determination and such equipment is expensive.
In some instances, it is useful to determine the amount of analyte in the test sample. For example, if a physician is treating a physical condition for a patient and the patient's blood is the test sample
A market demand exists for a simple, inexpensive system to determine whether a test sample of biological or chemical material being assayed includes a particular analyte, or a derivative or constituent of the analyte. There is also a market demand for quantifying the amount of includes a particular analyte, or a derivative or constituent of the analyte in an inexpensive system.